[lxc-devel] [PATCH 5/9] network: introduce a interface named lxc_netdev_isup().

[Serge Hallyn]

Quoting Serge Hallyn (serge.hallyn at ubuntu.com):
> Quoting Dongsheng Yang (yangds.fnst at cn.fujitsu.com):
> > When we need to know some info about a netdev, such as is_up or not,
> > we need to read the flag for the netdev.
> > 
> > This patch introduce a interface function named lxc_netdev_isup()
> > to check is a netdev up or down.
> > 
> > And introduce a network private function named netdev_get_flag()
> > to get flag for netdev by netlink.
> > 
> > Signed-off-by: Dongsheng Yang <yangds.fnst at cn.fujitsu.com>
> > ---
> >  src/lxc/network.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  src/lxc/network.h |  2 ++
> >  2 files changed, 69 insertions(+)
> > 
> > diff --git a/src/lxc/network.c b/src/lxc/network.c
> > index 4c577b1..e83b786 100644
> > --- a/src/lxc/network.c
> > +++ b/src/lxc/network.c
> > @@ -305,6 +305,73 @@ out:
> >  	return err;
> >  }
> >  
> > +int netdev_get_flag(const char* name, int *flag)
> > +{
> > +	struct nl_handler nlh;
> > +	struct nlmsg *nlmsg = NULL, *answer = NULL;
> > +	struct link_req *link_req;
> > +	int index, len, err;
> > +	struct ifinfomsg *ifi;
> > +
> > +	err = netlink_open(&nlh, NETLINK_ROUTE);
> > +	if (err)
> > +		return err;
> > +
> > +	err = -EINVAL;
> > +	len = strlen(name);
> > +	if (len == 1 || len >= IFNAMSIZ)
> > +		goto out;
> > +
> > +	err = -ENOMEM;
> > +	nlmsg = nlmsg_alloc(NLMSG_GOOD_SIZE);
> > +	if (!nlmsg)
> > +		goto out;
> > +
> > +	answer = nlmsg_alloc(NLMSG_GOOD_SIZE);
> > +	if (!answer)
> > +		goto out;
> > +
> > +	err = -EINVAL;
> > +	index = if_nametoindex(name);
> > +	if (!index)
> > +		goto out;
> > +
> > +	link_req = (struct link_req *)nlmsg;
> > +	link_req->ifinfomsg.ifi_family = AF_UNSPEC;
> > +	link_req->ifinfomsg.ifi_index = index;
> > +	nlmsg->nlmsghdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
> > +	nlmsg->nlmsghdr.nlmsg_flags = NLM_F_REQUEST;
> > +	nlmsg->nlmsghdr.nlmsg_type = RTM_GETLINK;
> > +
> > +	err = netlink_transaction(&nlh, nlmsg, answer);
> > +	if (err)
> > +		goto out;
> > +
> > +	ifi = NLMSG_DATA(answer);
> > +
> > +	*flag = ifi->ifi_flags;
> > +out:
> > +	netlink_close(&nlh);
> > +	nlmsg_free(nlmsg);
> > +	nlmsg_free(answer);
> > +	return err;
> > +}
> > +
> > +int lxc_netdev_isup(const char* name)
> > +{
> > +	int flag;
> > +	int err;
> > +
> > +	err = netdev_get_flag(name, &flag);
> > +	if (err)
> > +		goto out;
> > +	if (flag & IFF_UP)
> > +		return true;
> 
> Again, don't return true/false for an int.
> 
> I'd prefer this fn simply return bool.

Ok, disregard that.

Leave it returning an int, but return 1/0 explicitly,
and put a comment above the function detailing the
return values.  Then resend, with my

Acked-by: Serge E. Hallyn <serge.hallyn at ubuntu.com>

in reply to this email.

> > +	return false;
> > +out:
> > +	return err;
> > +}
> > +
> >  int netdev_get_mtu(int ifindex)
> >  {
> >  	struct nl_handler nlh;
> > diff --git a/src/lxc/network.h b/src/lxc/network.h
> > index 768489d..cd42c8f 100644
> > --- a/src/lxc/network.h
> > +++ b/src/lxc/network.h
> > @@ -51,6 +51,8 @@ extern int netdev_set_flag(const char *name, int flag);
> >  /*
> >   * Set the device network up or down
> >   */
> > +
> > +extern int lxc_netdev_isup(const char *name);
> >  extern int lxc_netdev_up(const char *name);
> >  extern int lxc_netdev_down(const char *name);
> >  
> > -- 
> > 1.8.4.2
> > 
> _______________________________________________
> lxc-devel mailing list
> lxc-devel at lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-devel